1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1995-1998 John Birrell <jb@cimlogic.com.au> 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. Neither the name of the author nor the names of any co-contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 */ 31 32 #include <sys/cdefs.h> 33 __FBSDID("$FreeBSD$"); 34 35 #include "namespace.h" 36 #include <errno.h> 37 #ifdef _PTHREAD_FORCED_UNWIND 38 #include <dlfcn.h> 39 #endif 40 #include <stdarg.h> 41 #include <stdio.h> 42 #include <stdlib.h> 43 #include <pthread.h> 44 #include <sys/types.h> 45 #include <sys/signalvar.h> 46 #include "un-namespace.h" 47 48 #include "libc_private.h" 49 #include "thr_private.h" 50 51 static void exit_thread(void) __dead2; 52 53 __weak_reference(_pthread_exit, pthread_exit); 54 55 #ifdef _PTHREAD_FORCED_UNWIND 56 static int message_printed; 57 58 static void thread_unwind(void) __dead2; 59 #ifdef PIC 60 static void thread_uw_init(void); 61 static _Unwind_Reason_Code thread_unwind_stop(int version, 62 _Unwind_Action actions, 63 int64_t exc_class, 64 struct _Unwind_Exception *exc_obj, 65 struct _Unwind_Context *context, void *stop_parameter); 66 /* unwind library pointers */ 67 static _Unwind_Reason_Code (*uwl_forcedunwind)(struct _Unwind_Exception *, 68 _Unwind_Stop_Fn, void *); 69 static unsigned long (*uwl_getcfa)(struct _Unwind_Context *); 70 71 static void 72 thread_uw_init(void) 73 { 74 static int inited = 0; 75 Dl_info dli; 76 void *handle; 77 void *forcedunwind, *getcfa; 78 79 if (inited) 80 return; 81 handle = RTLD_DEFAULT; 82 if ((forcedunwind = dlsym(handle, "_Unwind_ForcedUnwind")) != NULL) { 83 if (dladdr(forcedunwind, &dli)) { 84 /* 85 * Make sure the address is always valid by holding the library, 86 * also assume functions are in same library. 87 */ 88 if ((handle = dlopen(dli.dli_fname, RTLD_LAZY)) != NULL) { 89 forcedunwind = dlsym(handle, "_Unwind_ForcedUnwind"); 90 getcfa = dlsym(handle, "_Unwind_GetCFA"); 91 if (forcedunwind != NULL && getcfa != NULL) { 92 uwl_getcfa = getcfa; 93 atomic_store_rel_ptr((volatile void *)&uwl_forcedunwind, 94 (uintptr_t)forcedunwind); 95 } else { 96 dlclose(handle); 97 } 98 } 99 } 100 } 101 inited = 1; 102 } 103 104 _Unwind_Reason_Code 105 _Unwind_ForcedUnwind(struct _Unwind_Exception *ex, _Unwind_Stop_Fn stop_func, 106 void *stop_arg) 107 { 108 return (*uwl_forcedunwind)(ex, stop_func, stop_arg); 109 } 110 111 unsigned long 112 _Unwind_GetCFA(struct _Unwind_Context *context) 113 { 114 return (*uwl_getcfa)(context); 115 } 116 #else 117 #pragma weak _Unwind_GetCFA 118 #pragma weak _Unwind_ForcedUnwind 119 #endif /* PIC */ 120 121 static void 122 thread_unwind_cleanup(_Unwind_Reason_Code code __unused, 123 struct _Unwind_Exception *e __unused) 124 { 125 /* 126 * Specification said that _Unwind_Resume should not be used here, 127 * instead, user should rethrow the exception. For C++ user, they 128 * should put "throw" sentence in catch(...) block. 129 */ 130 PANIC("exception should be rethrown"); 131 } 132 133 static _Unwind_Reason_Code 134 thread_unwind_stop(int version __unused, _Unwind_Action actions, 135 int64_t exc_class __unused, 136 struct _Unwind_Exception *exc_obj __unused, 137 struct _Unwind_Context *context, void *stop_parameter __unused) 138 { 139 struct pthread *curthread = _get_curthread(); 140 struct pthread_cleanup *cur; 141 uintptr_t cfa; 142 int done = 0; 143 144 /* XXX assume stack grows down to lower address */ 145 146 cfa = _Unwind_GetCFA(context); 147 if (actions & _UA_END_OF_STACK || 148 cfa >= (uintptr_t)curthread->unwind_stackend) { 149 done = 1; 150 } 151 152 while ((cur = curthread->cleanup) != NULL && 153 (done || (uintptr_t)cur <= cfa)) { 154 __pthread_cleanup_pop_imp(1); 155 } 156 157 if (done) { 158 /* Tell libc that it should call non-trivial TLS dtors. */ 159 __cxa_thread_call_dtors(); 160 161 exit_thread(); /* Never return! */ 162 } 163 164 return (_URC_NO_REASON); 165 } 166 167 static void 168 thread_unwind(void) 169 { 170 struct pthread *curthread = _get_curthread(); 171 172 curthread->ex.exception_class = 0; 173 curthread->ex.exception_cleanup = thread_unwind_cleanup; 174 _Unwind_ForcedUnwind(&curthread->ex, thread_unwind_stop, NULL); 175 PANIC("_Unwind_ForcedUnwind returned"); 176 } 177 178 #endif 179 180 void 181 _thread_exitf(const char *fname, int lineno, const char *fmt, ...) 182 { 183 va_list ap; 184 185 /* Write an error message to the standard error file descriptor: */ 186 _thread_printf(STDERR_FILENO, "Fatal error '"); 187 188 va_start(ap, fmt); 189 _thread_vprintf(STDERR_FILENO, fmt, ap); 190 va_end(ap); 191 192 _thread_printf(STDERR_FILENO, "' at line %d in file %s (errno = %d)\n", 193 lineno, fname, errno); 194 195 abort(); 196 } 197 198 void 199 _thread_exit(const char *fname, int lineno, const char *msg) 200 { 201 202 _thread_exitf(fname, lineno, "%s", msg); 203 } 204 205 void 206 _pthread_exit(void *status) 207 { 208 _pthread_exit_mask(status, NULL); 209 } 210 211 void 212 _pthread_exit_mask(void *status, sigset_t *mask) 213 { 214 struct pthread *curthread = _get_curthread(); 215 216 /* Check if this thread is already in the process of exiting: */ 217 if (curthread->cancelling) 218 PANIC("Thread %p has called " 219 "pthread_exit() from a destructor. POSIX 1003.1 " 220 "1996 s16.2.5.2 does not allow this!", curthread); 221 222 /* Flag this thread as exiting. */ 223 curthread->cancelling = 1; 224 curthread->no_cancel = 1; 225 curthread->cancel_async = 0; 226 curthread->cancel_point = 0; 227 if (mask != NULL) 228 __sys_sigprocmask(SIG_SETMASK, mask, NULL); 229 if (curthread->unblock_sigcancel) { 230 sigset_t set; 231 232 curthread->unblock_sigcancel = 0; 233 SIGEMPTYSET(set); 234 SIGADDSET(set, SIGCANCEL); 235 __sys_sigprocmask(SIG_UNBLOCK, mask, NULL); 236 } 237 238 /* Save the return value: */ 239 curthread->ret = status; 240 #ifdef _PTHREAD_FORCED_UNWIND 241 242 #ifdef PIC 243 thread_uw_init(); 244 if (uwl_forcedunwind != NULL) { 245 #else 246 if (_Unwind_ForcedUnwind != NULL) { 247 #endif 248 if (curthread->unwind_disabled) { 249 if (message_printed == 0) { 250 message_printed = 1; 251 _thread_printf(2, "Warning: old _pthread_cleanup_push was called, " 252 "stack unwinding is disabled.\n"); 253 } 254 goto cleanup; 255 } 256 thread_unwind(); 257 258 } else { 259 cleanup: 260 while (curthread->cleanup != NULL) { 261 __pthread_cleanup_pop_imp(1); 262 } 263 __cxa_thread_call_dtors(); 264 265 exit_thread(); 266 } 267 268 #else 269 while (curthread->cleanup != NULL) { 270 __pthread_cleanup_pop_imp(1); 271 } 272 __cxa_thread_call_dtors(); 273 274 exit_thread(); 275 #endif /* _PTHREAD_FORCED_UNWIND */ 276 } 277 278 static void 279 exit_thread(void) 280 { 281 struct pthread *curthread = _get_curthread(); 282 283 free(curthread->name); 284 curthread->name = NULL; 285 286 /* Check if there is thread specific data: */ 287 if (curthread->specific != NULL) { 288 /* Run the thread-specific data destructors: */ 289 _thread_cleanupspecific(); 290 } 291 292 if (!_thr_isthreaded()) 293 exit(0); 294 295 if (atomic_fetchadd_int(&_thread_active_threads, -1) == 1) { 296 exit(0); 297 /* Never reach! */ 298 } 299 300 /* Tell malloc that the thread is exiting. */ 301 _malloc_thread_cleanup(); 302 303 THR_LOCK(curthread); 304 curthread->state = PS_DEAD; 305 if (curthread->flags & THR_FLAGS_NEED_SUSPEND) { 306 curthread->cycle++; 307 _thr_umtx_wake(&curthread->cycle, INT_MAX, 0); 308 } 309 if (!curthread->force_exit && SHOULD_REPORT_EVENT(curthread, TD_DEATH)) 310 _thr_report_death(curthread); 311 /* 312 * Thread was created with initial refcount 1, we drop the 313 * reference count to allow it to be garbage collected. 314 */ 315 curthread->refcount--; 316 _thr_try_gc(curthread, curthread); /* thread lock released */ 317 318 #if defined(_PTHREADS_INVARIANTS) 319 if (THR_IN_CRITICAL(curthread)) 320 PANIC("thread %p exits with resources held!", curthread); 321 #endif 322 /* 323 * Kernel will do wakeup at the address, so joiner thread 324 * will be resumed if it is sleeping at the address. 325 */ 326 thr_exit(&curthread->tid); 327 PANIC("thr_exit() returned"); 328 /* Never reach! */ 329 } 330